The present invention relates to a heat-treating technique, and more particularly to the heat treatment to a plate-like member such as a semiconductor wafer in the production of a semiconductor device.
As is well known, in case of producing semiconductor elements, the heat treatment of the semiconductor wafer is carried out in processes such as crystal growth, impurity diffusion, crystal annealing, passivation film forming, dry etching processing and photoresist baking.
Heretofore, heating systems employing a heater, high-frequency heating, etc., have been applied to these heat treatments. The heat-treating methods are such that the semiconductor wafer is supported by a jig or the like in a heating atmosphere and thus heated, or that the semiconductor wafer is directly put on a heating source such as a heating block and thus heat-treated. In any method, the wafer lies in contact with a supporter.
In order to precisely heat the wafer with the above methods, the supporting jig, heater block, or like support, must be precisely heated together with the wafer itself. Simultaneously, the surrounding inner wall of a processing chamber is heated. With the above methods, therefore, the heating efficiency is very inferior, and the processing time is long. Another disadvantage is that, when the jig or the heater block is large, the heat-treating apparatus becomes large in size.
Similarly, in the heat treatment accompanied with a reaction, that part other than the wafer which does not require the reaction, is heated. Therefore, the reaction takes place in the part other than the wafer requiring no reaction, and an unnecessary product is formed on the supporting jig of the object to be heat-treated or the inner wall of the processing chamber. As a result, in case of manufacturing a semiconductor element by the heat treatment accompanied with a reaction, the product falls on the wafer in which the semiconductor element is formed, to incur the degradation of the quality of the manufactured semiconductor element.
Also, incidental operations such as the operation of clearing away the unnecessary product formed on the inner wall of the processing chamber increase.
Also, in case of the foregoing heat-treatment, it is difficult to only heat the wafer.